The present invention relates to an improved locking device comprised of a housing assembly and a separable cylinder assembly.
In U.S. Pat. No. 3,824,817 issued July 23, 1974, a removable cylinder lock especially useful in combination with furniture, office, business equipment or the like was disclosed. The removable cylinder lock included a housing with a bolt. The housing and bolt would normally be installed in the furniture, office business equipment or the like as part of the furniture. A cylinder would then be attached to the housing by a locking spring in the housing. Consequently, the tumbler mechanism of the cylinder would not be exposed to the furniture finishing process. Lock hardware would be added following final assembly of the furniture or could be changed if failure occurred or the key combination required change.
The separation of the housing and bolt into a separate sub-assembly from the key locking assembly is a valuable benefit to the original equipment manufacturer. It relieves him of all record keeping and responsibility for keying and key changes of the locks that are subsequently installed in his product (drawers, doors, furniture etc.) in the field by the lock user. The manufacturer need only install the housing and bolt sub-assembly. The locks are installed by the user of the furniture. This has also been an aid to the lock user, in the case of banks, wherein the locks, keyed differently, can be easily changed from place to place with the use of the change key.
U.S. Pat. No. 3,824,817 discloses a removable lock cylinder which relies upon utilization of a bifurcated spring that grips and retains the cylinder in the housing. To disengage the cylinder, the bifurcated spring is flexed by a tool insertable from the back of the housing. While such a structure worked in an adequate and sufficient manner, manufacture of the bifurcated spring to obtain consistent spring quality has proven to be overly expensive. Thus, an improved control mechanism for locking and retaining the cylinder assembly in the housing assembly is desirable.